One vertex per element, one color per generator, with an edge from x to x·s.
(1,2,4,6)(3,5,7,8)(9,10)(11,12)(13,21)(14,18)(15,16)(17,22)(19,23)(20,24)(25,26,31,35)(27,36,37,32)(28,29,33,38)(30,39,40,34)(3,7)(5,8)(9,11,14,16)(10,12,18,15)(13,19,22,24)(17,20,21,23)(25,27)(26,32)(28,30)(29,34)(31,37)(33,40)(35,36)(38,39)(1,2)(3,5)(4,6)(7,8)(9,11)(10,15)(12,18)(13,19)(14,16)(17,23)(20,21)(22,24)(25,28,31,33)(26,29,35,38)(27,30,37,40)(32,34,36,39)(1,3)(2,5)(4,7)(6,8)(9,11)(10,12)(13,19)(14,16)(15,18)(17,20)(21,23)(22,24)(25,26)(27,32)(28,29)(30,34)(31,35)(33,38)(36,37)(39,40) involution — undirected(1,2)(3,5)(4,6)(7,8)(9,12)(10,16)(11,18)(13,20)(14,15)(17,24)(19,21)(22,23)(25,29)(26,33)(27,34)(28,35)(30,36)(31,38)(32,40)(37,39) involution — undirected(9,13,14,22)(10,17,18,21)(11,19,16,24)(12,20,15,23)(25,30,31,40)(26,34,35,39)(27,28,37,33)(29,36,38,32)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.